The present invention relates to a method for producing press-hardened components, in particular motor vehicle body components, from a plate of unhardened, hot-formable steel sheet. In the method, the plate is hot-formed and hardened in a press tool, thereby creating a sheet profile.
Prior art DE 24 52 486 A1 discloses a method for producing a hardened sheet profile from a plate in a press-hardening process. A plate comprising a hardenable steel is heated to hardening temperature, and then is hot-formed in a press tool, and subsequently hardened while the sheet profile remains in the press tool. A product with good dimensional stability is obtained, since the sheet profile is held in the press tool during the cooling that occurs during the hardening process.
Hot-forming and hardening in a press tool is an economical operating method, because both the forming and the hardening or aging processes are combined in a single tool.
Given this background, WO 2005/018848 A1 describes methods in which a component blank is formed initially using a cold-forming process, in particular a drawing process, and the margin of the component blank is then trimmed to correspond approximately to the marginal contour of the component to be produced, or, wherein after the forming and hardening processes, the margin of the press-hardened component blank is cut to correspond to the marginal contour of the component to be produced. The press-hardened component blank is coated with an anti-corrosion layer in a subsequent processing step.
In general, profile components made of sheet steel, especially motor vehicle components, are provided with a surface coating to protect against corrosion. Applying the surface coating to the component using a thermal diffusion method is known. This is explained in WO 2005/018848 A1, inter alia. A layer of zinc or a zinc alloy is preferably applied as a surface coating.